Concrete Scanning for Structural Engineers: A Practical Guide
GPR concrete scanning and NDT testing generate precise, certifiable data about what's inside a concrete structure. Here's how to use that data effectively in your structural assessments — and how to specify it correctly in your scope.
What Data Does GPR Concrete Scanning Provide?
GPR concrete scanning provides a subsurface map of all embedded elements within a concrete structure. For structural engineers, the key data outputs are:
Rebar location & spacing
Exact position of reinforcing bars in plan and elevation — critical for load capacity assessments and modification approvals.
Rebar cover depth
Depth of reinforcement from the concrete surface — essential for durability assessments, carbonation risk, and concrete cancer evaluations.
Post-tension cable positions
Location of PT cables with depth measurements — mandatory before any penetration works on PT slabs.
Embedded conduits & services
Electrical conduits, plumbing, and data cables mapped in 3D — prevents service strikes and coordinates with services engineers.
Voids & delaminations
Areas of internal concrete defects, delaminations, or honeycombing — indicates construction defects or deterioration.
Slab thickness
Measured using GPR reflection data — useful when as-built drawings are unavailable or unverified.
How to Read a GPR Report
Delco Industries provides GPR reports in both CAD-compatible formats and PDF. Understanding the key elements:
Plan view map
Top-down view of the scan area showing embedded object locations. Rebar shown as grid lines, PT cables as parallel lines, conduits as single lines.
Depth annotations
Numbers adjacent to each element indicate depth from surface in millimetres. Critical for calculating cover and avoiding strikes.
Colour coding
Red = high-confidence features (strong reflectors, e.g. rebar, PT cables). Orange/yellow = medium confidence. Grey = uncertain features requiring further investigation.
Radargram
Cross-sectional view of scan data showing reflected wave amplitudes with depth. Experienced engineers can identify object types from radargram profiles.
Safe zone marking
Green zones marked directly on the physical slab surface indicating locations cleared for drilling or cutting.
Integrating Scan Data into Structural Assessments
GPR concrete scanning and NDT structural analysis data integrates directly into structural engineering workflows:
As-built verification
Compare GPR rebar layout against design drawings to identify construction non-conformances.
Load capacity assessment
Verified rebar size, spacing and depth data feeds directly into capacity calculations for slab modifications or additional loading.
BIM model population
3D scan data exports in formats compatible with Revit, AutoCAD, and other BIM platforms — enabling digital twin creation.
Condition assessment reporting
NDT data (UPV, half-cell potential, carbonation depth) provides the quantitative evidence base for structural condition reports and durability assessments.
Remediation scoping
Void, delamination and concrete cancer data directly informs repair area mapping and remediation specification.
How to Specify Scanning in Your Scope
Recommended specification language for structural engineering scopes:
// Sample specification clause
Prior to any concrete drilling, coring, or cutting works, the contractor shall engage a specialist GPR concrete scanning company to conduct a pre-scan of all proposed penetration and cutting locations. A scan report shall be provided to the Engineer of Record prior to works commencing. All drill and cut locations shall be marked on the slab surface by the scanning technician indicating clearance from embedded elements. A minimum clearance of [X]mm from post-tension cables and [X]mm from primary reinforcement shall be maintained.
Delco Industries' Deliverables for Structural Engineers
We operate across South East Queensland — GPR concrete scanning Brisbane, GPR concrete scanning Gold Coast, and regional QLD. All deliverables include engineer-signed certification.
GPR Concrete Scanning
CAD plan + PDF report + on-slab markings
Report: Same dayNDT Structural Analysis
Certified report with UPV, rebound & corrosion data
Report: 48 hoursPile Integrity Testing
Engineer-certified PIT report + integrity classification
Report: 48 hours3D AR Imaging
3D model export + BIM-compatible files
Report: 3–5 daysVoid & Delamination
Colour-coded defect map + area calculations
Report: 48 hoursCrack Mapping
HD photo documentation + crack pattern maps
Report: 48 hoursRelated Services